GB2067272A

GB2067272A - Centre link disc valve

Info

Publication number: GB2067272A
Application number: GB8100581A
Authority: GB
Original assignee: Koppers Co Inc
Current assignee: Beazer East Inc
Priority date: 1980-01-09
Filing date: 1981-01-09
Publication date: 1981-07-22
Also published as: CA1133451A; GB2067272B; US4280681A

Description

1 GB 2 067 272 A 1

SPECIFICATION Centre link disc valve

This invention relates to disc-type valves for control of the flow of materials and more particularly to such valves in which movement of the valve disc on opening includes a lateral movement away from the valve seat.

According to the present invention there is provided a valve including a disc, a seat therefor, -10 cam means and track means adapted to cooperate therewith, and means for effecting rotation of the disc about a transverse axis of the valve, wherein operation of the means for effecting rotation so as to open the valve from its closed position causes an initial retraction of the disc from the seat in a linear direction about the longitudinal axis of the valve followed by rotation of the disc about a transverse axis of the valve, the position of the disc in relation to the longitudinal axis of the valve being determined by the position of the cam means in relation to the track means in such a way that the angle of incidence of the disc from the longitudinal axis of the valve in the rotational phase of the disc movement is proportional to the extent of rotation of the means 90 for effecting rotation.

Preferably the means for effecting rotation of the disc is a rotatable shaft extending parallel to and spaced from a transverse axis of the valve and connected to the disc by means of an arm 95 extending from about the mid-point of the shaft perpendicular to the shaft, to the end of which arm is pivoted one or two links curved so as to avoid the shaft when the end of the arm is at or past top dead centre, and to the other end or ends of which 100 links is connected a clevis, which in turn is fixed to the disc itself.

Conveniently the disc has mounted upon it guides, either one or two, in which latter case they are mounted symmetrically opposite each other, 105 and in both cases at the periphery of the disc and perpendicular to its plane or principal plane. The guides may be supported by bracing or strengthening structures, but the guides themselves are constituted by pronged fork 110 constructions so arranged that the prongs extend towards the rotatable shaft and pass on either side of it so as to accommodate a cross-section of the shaft between the prongs.

Desirably, the pronged fork construction moves 115 in relation to the rotatable shaft in such a way that upon retraction of the disc from the seat the prongs move relatively to the shaft so as to fully engage the cross-section of the shaft with the head of the pronged fork construction and on 120 rotation of the disc the shaft remains fully engaged. As a corollary, when M disc is engaged with the seat, the shaft is not fully engaged with the head of the fork.

Suitably, the cam means and the track means co-operating with it, include one or more cams mounted each in one of the guide means so as to be rotatable about its own longitudinal axis but not otherwise movable in the guide means, the track means being the inside edge of an aperture in a plate whose centre is concentric with the longitudinal axis of the shaft and which is perpendicular to that axis. The plate should be spaced apart from the periphery of the disc so that the rotatable shaft passes through the guide means and then through the plate in the direction of passing from the interior of the valve to the outside of the valve.

Advantageously the aperture in the plate has an outline including a straight section and an arcuate section, the arcuate section being adjacent to the longitudinal axis of the shaft.

The invention will now be described, by way of example, with reference to the accompanying, partly diagrammatic, drawings, in which:

Figure 1 is a cut away projection view of a disc valve; Figure 2 is a plan view of a detail of the disc valve showing the arrangement of the centre link mechanism in relation to the disc and the rotatable shaft; Figure 3 is a cross-sectional plan view of a detail of the disc valve showing the arrangement of the cam housing in relation to the disc and rotatable shaft; Figure 4 is a cross-sectional side elevation of the cam housing, on the line IV-IV of Figure 7; Figure 5 is a cross-sectional side elevation of the centre link mechanism in relation to the disc and the rotatable shaft, on the line V-V of Figure 7; Figure 6 is a cross-sectional side elevation of the guide in relation to the disc and the rotatable shaft, on the line VI-V1 of Figure 7; Figure 7 is a cross-sectional end elevation of the cam housings and centre link mechanism in relation to the rotatable shaft; and Figure 8 is a cross-sectional end elevation of the cam housings and centre link mechanism in relation to the rotatable. shaft, taken at the other end to that of Figure 7.

As shown in Figures 1, 7 and 8, a valve body 11 has a tubular shell 13 with a front flange 15 and a rear flange 17, each having a plurality of bolt apertures 19 to permit of fastening to corresponding flanges (not shown) in a pipe-line system. Also fixed to the tubular shell 13 is a valve seat 21 in the form of a flat annular ring, the outer circumference of which is fixed to the interior surface of the tubular shell 13 adjacent to the front flange 15.

A rotatable shaft 23 is directed transversely through the tubular shell 13 in a position which is perpendicular to the longitudinal axis of the tubular shell 13. Circumferentially and coaxially surrounding each end of the rotatable shaft 23 is a cam housing 25. The two cam housings 25 are mounted on the tubular shell 13 opposite each other with the rotatable shaft 23 extending therethrough. Each of the cam housings 25 incorporates a tubular extension 27 which is fixed at the periphery of an operating aperture 29 positioned in the outer surface of the tubular shell 13 and being coaxial with the rotatable shaft 23.

2 Each tubular extension 27 has an outer end 3 1, on which is mounted a plate flange 33. Removably mounted on each of the plate flanges 33 is a bearing mount plate 35. Both the plate flanges 33 and the bearing mount plates 35 have alignable bolt apertures 37 to permit the bearing mount plates 35 to be bolted to the plate flanges 33. Fixed through each bearing mount plate 35 is a tubular bearing support sleeve 39 which is aligned and coaxial with the axis of the rotatable shaft 23 75 when the corresponding bearing mount plate 35 is mounted on its plate flange 33. Mounted within each bearing support sleeve 39 is a shaft bearing 41 of oil impregnated bronze. Alternatively, a roller or ball bearing may be used instead of a shaft bearing. At the outer end of each bearing support sleeve 39 is fixes a sleeve flange 43.

The rotatable shaft 23 extends coaxially through the shaft bearings 41 which, in turn, are coaxially mounted within the bearing support sleeves 39. Thus, the rotatable shaft 23 is movably mounted near its two ends in the shaft bearings 41 and is supported thereby. At the outer end of each shaft bearing 41 is a packing gland 45 that functions to prevent the material traversing the valve when in use from leaking out past the shaft bearing 41. Conventional saturated ropetype packing material may be used in such packing glands 45 or other types of packing materials well known in the art may be used. A packing compression sleeve 47 is applied to each packing gland 45 to compress the material of the packing gland 45 and insure that it forms a fluidtight seal. A compression flange 49 is fixed to each packing compression sleeve 47 as shown in Figure 8. A plurality of draw fasteners 51 is used to secure each compression flange 49 to the corresponding sleeve flange 43, and to draw the packing compression sleeve 47 into bearing support sleeve 39 to compress packing gland 45. 105 The rotatable shaft 23 extends, outwardly, further from the bearing support sleeve 39 and packing compression sleeve 47 at one end 53 than it does at the other which is provided with a lever means 55 for rotating the rotatable shaft 23. 110 Lever means 55 is connected to be actuated by an hydraulic cylinder (not shown). Alternatively, for manual operation of the valve a wheel or a crank may be used.

Fixed to each plate flange 33, and within 115 tubular extension 27, is a track suspension sleeve 57 which extends towards the centre of the valve, from the plate flange 33 and is coaxial with the corresponding tubular extension 27. Each track suspension sleeve 57 is buttressed at its inner end 120 with a track 59 which takes the form of a circular plate having an aperture cut therethrough. As shown in Figure 4, the periphery of the aperture is a straight slot section 61 which translineates into an arcuate slot section 63 describing 90 degrees of are. A portion of the aperture is a circular clearance port 65 through which the rotatable shaft 23 extends.

At approximately the longitudinal mid-point of that portion of the rotatable shaft 23 which 130 GB 2 067 272 A 2 extends through and inside the valve body 11 is positioned a lever arm 67 which is fixed to the rotatable shaft 23 and is perpendicular to its longitudinal axis. A pair of curved links 69 is pivotably mounted on the lever arm 67, at the end distanced from the rotatable shaft 23. The axis of rotation of the mount of the curved links 69 to the lever arm 67 is parallel to the longitudinal axis of the rotatable shaft 23. As shown in Figure 2, curved links 69 pivot upon lever arm 67 by means of a bolted stud assembly 7 1.

Each of the curved links 69 is of such arcuate form that when the pair are pivoted in relation to the lever arm 67, towards the rotatable shaft 23, the interiors of the arcs traced by the curved links 69 partially encompass the rotatable shaft 23. The distanced ends of the curved links 69 are mounted on a clevis 73 by a bolted stud assembly 75.

The clevis 73 is fixed centrally to a valve disc 77 which is circular and generally flat, and functions to open and close the valve. The valve disc 77 is shown in Figure 1 in the fully open position and is shown in Figures 4, 5, 6, 7 and 8 in the fully closed position. Sectional portions of the valve disc are shown in Figures 2 and 3 in the fully closed position.

The valve disc 77 may either be a flat plate type or a dish type. In operation the valve is mounted such that, when the valve disc 77 is in the closed position, the higher line pressure is on the clevis 73 side of the valve disc 77.

In the closed position, the valve disc 77 rests on the valve seat 21 as shown in Figures 3, 5 and 6. Interposed between the mating surfaces of the valve disc 77 and the valve seat 21 is seal means 79 consisting of an elastomer seal ring of a size compatible with the periphery of the valve disc 77. As an alternative, the seal means 79 may, however, function on the basis that the surfaces of the valve seat 21 and the valve disc 77 are of metals, one of which is softer than the other, either by using separate rings or having integrally formed surfaces of relatively different hardnesses. Such metals might be soft aluminium, or copper with a low temper.

The valve disc 77 and the rotatable shaft 23 are positioned and arranged such that at all times the longitudinal axis of the rotatable shaft 23 is parallel with but distanced from the principal plane of the valve disc 77. The valve disc 77 moves at all times in relation to the rotatable shaft 23 which is not displaced but rotates about its longitudinal axis, so that this axis serves as the axis of rotation of the valve disc as it rotates through a 900 arc as hereinafter described.

Adjacent to the rotatable shaft 23 and at the periphery of the valve disc 77 are positioned, respectively, a pair of guides 8 1, fixed to the valve disc 77, as shown in Figures 1, 6, 7 and 8. Each of the guides 81 consists of a base 83 in the form of a flat plate, fixed to the valve disc 77, by nut and bolt assemblies 85 as shown in Figure 6. Perpendicular to each base, extending away from the valve disc 77 towards the rotatable shaft 23, is a two-pronged fork 87 having an internal part- 41 3 circular section 89 between the two prongs, as shown in Figure 6. Each of the forks 87 is positioned at the periphery of the valve disc 77 upon its corresponding base 83. Each of the guides 81 includes a pair of braces 91 which support and are fixed to their respective forks 87, as shown in Figure 1.

The two prongs of each fork 87 extend so that they partially envelop a transverse section of the 0 rotatable shaft 23. Where contiguity occurs, as between the fork 87 and the rotatable shaft 23, a guide bearing 93 is mounted on the rotatable shaft 23. In a preferred embodiment, the guide bearings 93 are bronze bushings fitted over the rotatable shaft 23 and positioned so as to be aligned with the forks 87 to which each corresponds. The internal radius 89 (Figure 6) of each of the forks 87 is equal to the external radius of the corresponding guide bearing 93. Thus, in operation, the valve disc 77 moves longitudinally away from valve seat 21 and as this occurs, the forks 87 move laterally across the guide bearings 93 until the internal radius 89 of each fork 87 butts up against the corresponding guide bearing 93.

Rotatably mounted on the outward side of each guide 81 is a cam 95 as shown in Figures 3 and 4. Referring now to Figure 8, each cam includes a rotatable cam spindle 97 which extends through a fixed cam bearing 99, this being mounted in a mounting aperture in the corresponding fork 87 at a position between the internal radius 89 and the base 83 thereof. A cam roller 101 is secured to each cam spindle 97 and is aligned with the corresponding track 59.

Referring again to Figure 4, the valve is in its fully closed position. Cam 95, with the cam roller 101, is at the forward end of straight slot section 61. The fork 87 of the guide 81 has its internal radius 89 displaced forwardly from the guide bearing 93. The lever arm 67, shown in Figure 5, is disposed in relation to the curved links 69 in its most open position so that the angle between the lever arm 67 and the curved links 69 is at its greatest extent, and the curved links 69 thereby are caused to exert pressure through the clevis 73 on valve 77, thereby urging it towards the valve seat 21 so as fully to engage the seal means 79 with the valve seat 2 1.

-50 To open the valve, the rotatable shaft 23 is rotated anti-clockwise in relation to the closed position of the valve shown in Figure 5, through the operation of the means 55. As the rotatable shaft 23 is rotated, the valve disc 77 moves away from the valve seat 21 but remains parallel with the plane of the valve seat 2 1. In so doing the valve disc 77 moves towards the rotatable shaft 23 but the longitudinal axis of the rotatable shaft 23 remains parallel with the principal plane of valve disc 77. Thus, the valve disc 77 has been 125 moved longitudinally away from the valve seat 2 1, so that the seal means 79 has been lifted uniformly off the valve seat 2 1. This has been achieved by means of the cam roller 10 1 moving, initially, within the straight slot section 61 of the 130 GB 2 067 272 A 3 track 59. The position of the cam roller 10 1 Is fixed in relation to the valve disc 77, since the cam roller 101 is fixed in a transverse plane by being part of cam 95, which itself is mounted in the fork 87, this being fixed to the valve disc 77. Thus, the valve disc 77 is prevented from moving in any direction other than longitudinally away from the valve seat 2 1, as the rotatable shaft 23 is rotated. Guides 81 maintain the parallelism of the valve disc 77 in relation to the longitudinal axis of the rotatable shaft 23 and also prevent any rotation of the valve disc 77 about the longitudinal axis of the rotatable shaft 23 while the cam rollers 101 are engaged within the straight slot section 61 of the tracks 59.

The anti-clockwise rotation of the rotatable shaft 23 is translated into linear movement of valve disc 77 by means of the end of lever arm 67 distanced from the rotatable shaft 23 also being rotated about the bolted stud assembly 71 in an anti-clockwise direction. As this occurs, the curved links 69 draw the valve disc 77 linearly and longitudinally away from the valve seat 2 1. As the valve disc 77 moves away from the valve seat 2 1, the guides 81 thereby move so that the internal radius 89 of each fork 87 is brought into contact with the guide bearing 93.

From the position just referred to, as the rotatable shaft 23 is continued to rotate anti- clockwise, the valve disc 77 is caused to pivot from the vertical to the horizontal in relation to the longitudinal axis of the valve, through approximately 90 degrees of arc, thus fully opening the valve. However, the rotational movement of the valve disc 77 may be halted at any point on the arc to effect control of the rate of flow of material passing through the valve.

As the valve disc 77 begins to pivot, the cam roller 101 leaves the straight slot section 61 of the track 59 and enters the arcuate slot section 63 of track 59. The valve disc 77 continues to pivot, and as it does so, the cam roller 101 traverses the arcuate slot section 63, finally reaching the end of the arcuate slot section 63 that is, as part of the track 59, vertically below the longitudinal axis of the rotatable shaft 23, so that the position of the cam roller 101 is vertically coplanar with that axis. On the completion of rotation of the valve disc 77, the guide 81 having also been rotated through 90 degrees of arc about the longitudinal axis of the rotatable shaft 23, each fork 87 has changed from a horizontal to a vertical disposition. During this aspect of the sequence of opening of the valve, each internal radius 89 remains in contact with the guide bearing 93. The valve disc 77 comes to rest in the fully open position against a peg 103, shown in Figures 1, 3, 6, 7 and 8, which peg is fixed to each tubular extension 27.

During the rotation of valve disc 77 from the vertical to the horizontal aspect, the lever arm 67 rotates about the longitudinal axis of the rotatable shaft 23 in an anti-clockwise direction, and the curved links 69 rotate about the bolted stud assembly 7 1. When the valve is closed, the bolted stud assembly 71 is vertically below the 4 GB 2 067 272 A 4 longitudinal axis of the rotatable shaft 23. As the lever arm 67 rotates so that the valve disc 77 moves longitudinally and linearly away from the valve seat 2 1, the position of the bolted stud assembly 71 is above bottom dead centre and is moving in an anti- clockwise direction. When the valve disc 77 is in the fully open position and is horizontal, the lever arm 67 has rotated about the longitudinal axis of the rotatable shaft 23 so that the longitudinal axis of the lever arm 67 is just above the horizontal. The curved links 69 have further rotated about the bolted stud assembly 71 so that the curved links 69 are now on the side of the rotatable shaft 23, nearer the rear flange 17 of the valve body 11, but distanced from the rotatable shaft 23. It should be noted that during the rotation of the valve disc 77 the angle between the longitudinal axis of the lever arm 67 and a plane drawn between the bolted stud assembly 71 and the means 75, and between this plane and the principal plane of the valve disc 77 has not changed.

To close the valve, the sequence of operation is merely reversed, the rotatable shaft 23 being rotated in the opposite direction to that when the valve is opened.

Claims

1. A disc-type valve, including a disc, a seat therefor, cam means and track means adapted to co-operate therewith, and means for effecting rotation of the disc about a transverse axis of the valve, wherein operation of the means for effecting rotation so as to open the valve from the closed position thereof causes an initial retraction 35. of the disc from the seat in a linear direction about the longitudinal axis of the valve followed by rotation of the disc about a transverse axis of the valve, the position of the disc being determined by the position of the cam means in relation to the track means such that the angle of incidence of the disc ' to the longitudinal axis of the valve in the rotational phase of the movement of the disc is proportional to the extent of rotation of the means for effecting rotation.

2. A valve as claimed in Claim 1, wherein the means for effecting rotation of the disc is a rotatable shaft extending parallel to and spaced from a transverse axis of the valve, an arm fixed to the rotatable shaft and perpendicular to its longitudinal axis, a link arranged to be capable of pivoting about the end of the arm distanced from the rotatable shaft, and means for fixing the end of the link distanced from the arm to the disc.

3. A valve as claimed in Claim 2, wherein the link is a pair of curved links adapted to clear the rotatable shaft during operation of the means for effecting rotation and arranged to be capable of pivoting each on either side of the end of the arm distanced from the rotatable shaft.

4. A valve as claimed in Claim 3, wherein the 125 means for fixing the end of the link distanced from the arm to the disc is a clevis connected to both the link and the disc.

5. A valve as claimed in any one of Claims 1 to 4, wherein the seat is an annulus mounted within the valve such that the surface of the annulus against which the disc abuts upon closure of the valve is perpendicular to the longitudinal axis of the valve.

6. A valve as claimed in Claim 5, wherein the seat carries seal means arranged to be interposed z between the seat and the disc upon abutment of the disc with the seat.

7. A valve as claimed in Claim 6, wherein the.

seal means is either an elastomeric seal ring or is made of metal of substantially different hardness to that of the disc.

8. A valve as claimed in any one of Claims 2 to 7, wherein the longitudinal axis of the rotatable shaft is parallel to the principal plane of the disc.

9. A valve as claimed in any one of Claims 1 to 8, wherein the disc is substantially flat.

10. A valve as claimed in any one of Claims 1 to 9, wherein the disc is provided, at at least one position on the periphery thereof, and adjacent to the shaft, with guide means each perpendicular to the principal plane of the disc and fixed thereto.

11. A valve as claimed in Claim 10, wherein two guide means we provided, each at a mutually opposite position on the periphery of the disc.

12. A valve as claimed in either Claim 10 or Claim 11, wherein the guide means includes a two-prong fork construction so arranged that the prongs extend towards the rotatable shaft, each prong being parallel to the other prong of its construction, and having a gap therebetween so as to be capable of accommodating the crosssection of the rotatable shaft.

13. A valve as claimed in Claim 12, wherein when the disc is engaged with the seat a crosssection of the rotatable shaft is not engaged with the head of a fork construction, and when the disc is retracted from the seat and thereafter rotates, a cross-section of the rotatable shaft is engaged with the head of the fork construction.

14. A valve as claimed in any one of Claims 10 to 13, wherein at least one stop is provided such that the disc is prevented from moving beyond the position where its principal plane is parallel with the longitudinal axis of the valve.

15. A valve as claimed in Claim 14, wherein two stops are provided, each at an opposite and mutually symmetrical position adjacent to the periphery of the disc.

16. A valve as claimed in either Claim 14 or Claim 15, wherein the or each stop is a peg secured to the inside of the valve and adapted to engage with the guide means when the principal plane of the disc is parallel with the longitudinal axis of the valve.

17. A valve as claimed in any one of Claims 10 to 16, wherein the cam means includes a cam mounted so as to be rotatable only about its longitudinal axis in at least one of the guide means, the cam being adapted to move over a track constituted by part of the periphery of an aperture in an annular plate whose centre is on and whose plane is perpendicular to the GB 2 067 272 A 5 longitudinal axis of the rotatable shaft.

18. A valve as claimed in Claim 17, having cam means mounted in each of two guide means, the guide means being provided each at a mutually opposite position on the periphery of the disc and each adjacent to the rotatable shaft.

19. A valve as claimed in any one of Claims 2 to 18, wherein the track means includes a track having a linear section next to an arcuate section, the arcuate section being adjacent to the longitudinal axis of the rotatable shaft.

20. A valve as claimed in Claim 19, wherein the arcuate section of the track describes 90 degrees of arc.

2 1. A valve arranged and adapted to operate substantially as herein described with reference to the accompanying drawings.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1981. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.